Lead-bath apparatus for working ores



2 Sheets-Sheet 1.

(No Model.)

A. M. SHIELDS.

LEAD BATH APPARATUS FOR WORKING ORES.

No. 393,454. Patented Nov. 27, 1888.

N. PEIERS. Pnbwwm n mr, Waishingion. ac.

2 Sheets-Sheet 2.

(No Model.)

A. M. SHIELDS.

LEAD BATH APPARATUS FOR WORKING DEBS.

Patented Nov. 2'7

UNITED STATES PATENT Erica,

ANDREW M. SHIELDS, OF NORTH TEMESCAL, CALIFORNIA.

SPECIFICATION forming part of Letters Patent No. 393,454, dated November 27, 1888.

Application filed December 30, 1887. Serial No. 250,436.

To aZZ whom it may concern:

Be it known that I, ANDREW M. SHIELDs, of North Temescal, Alameda county, State of California, have invented an Improvement in a Lead-Bath Apparatus for Working Ores; and I hereby declare the following to be a full, clear, and exact description of the same.

My invention relates to an apparatus in which melted lead is employed as a bath, and fine pulverized ore or sand which bears precious metals is forced through the bath for the purpose of extracting the metal therefrom.

My invention consists of a pan, the bottom of which stands at an incline, while the top is in a nearly-horizontal plane, and in combina' tion with this pan a means for reducing the surface of melted lead exposed to the atmosphere, the means for feeding the sand or ma terial to be treated beneath the molten metal, and the means for agitating the same, together with a means for discharging the refuse from the top of the lead bath without carrying away the lead itself.

It also consists in certain details of construction, all of which will be more fully explained by reference to the accompanying drawings, in which Figure 1 is a perspective view of my apparatus. Fig. 2 is a longitudinal vertical section. Fig. 3 is a sectional view taken through X X of Fig. 2, showing the lead-bath chamber partially in perspective and the stirrers or agitators within it.

In the employment of molten lead or other metal to recover precious metals from their ores, or from sand with which they may be mixed, considerable difficulty has been experienced, first, from the large surface of lead which must be exposed to the atmosphere, and the consequent loss from oxidation; secondly,in the difficulty of distributing the sand so that all parts will be exposed to the action of the metal; and, thirdly, in the difficulty of separating the sand from the lead and discharging it without carrying off a considerable quantity of the lead with it. My invention is designed to overcome these difficulties, and is constructed as follows:

A is the pan, having a bottom and straight or slightly-flaring sides extending upwardly from this bottom. The top of the pan is out (No model.)

off at an angle, as shown, so that one of the sides will be very deep while the other will be comparatively shallow, or with practically no depth at all. The pan is then set so that its bottom stands at an angle, as shown in Fig. 2, and this beveled top stands in a nearlyhorizontal position. \Vithin this pan is fixed a second interior pan, B, the bottom of which stands at a sutiicient distance above the bottom of the pan A to admit of a circular carrier, 0. This disk 0 is fixed to the shaft D, the lower end of which is journaled in the step E in the center of the bottom of the pan. The shaft D extends upwardly at right angles with the bottom of the pan A, having a corresponding inclination with the horizon, as shown. Upon the top of this shaft is a driving-pulley, E, through which motion is imparted to it, and the shaft and the disk 0 are thus caused to re- .volve between the bottoms of the two pans A and B, which are parallel to each other.

Around the periphery of the disk 0 are the raised flanges, which form circular channels F F between them. Upon the upper or shallow side of the pan A is formed a feed-opening, G, into which the material to be treated is fed, and it falls directly into the channels F F of the rotating disk 0, these channels passing directly under the feed opening at their highest point. The continued revolution of the disk 0 carries the material which is fed into the channels down to the deepest part of the pan A and beneath the bath of melted lead which stands in the pan. The lower and deeper side of the pan B has an enlargement or chamber, H, into which the melted metal rises, so that its upper sn rface stands just level with the upper edge of the chamber, and the incline of the pan is such that the metal does not reach quite to the upper edge of the disk 0, thus leaving the channels F exposed beneath the feed-opening G, so that the material can fill them, and as the disk rotates the material will be carried beneath the molten lead, as above described, the pressure of the lead serving to keep it within the channels until it is lifted out mechanically.

In order to remove the material from the channels 0 when they arrive at'the lowest point and beneath the chamber H, I employ a scraper, 1, which is fixed to the apparatus so that the points of the spades extend into the channels F, standing at a considerable inclination, so that the sand and material will be lifted out of the channels and caused to rise through the molten mass of lead which fills the chamber H. In order to thoroughly distribute this material and expose it to the action of the molten metal, I employ a distributor, which is constructed as follows:

J Jare arms or crosses secured to the shafts K and K, which extend horizontally across the chamber H near the bottom. The shaft K is of smaller diameter than the shaft K, and the latter is hollow, so that the shaft K extends through it. One of the crosses, J, is sccured to the shaft Kand the other to K. Out side of the chamber H the shafts K and K have beveled gears L and L, which engage upon opposite sides of the corresponding beveled gear, M, which is secured to the vertical d riving-shaft N, so that by this arrangement the shafts K and Kand the crosses J Jare driven in opposite directions. The shaft N has a pulley at the top to receive a drivingbelt from the central shaft, 1). From these crosses or arms J bars 0 and O extend horizontally, the bars 0 from the cross J extending nearly to the face of the cross J, while the bars 0 from the cross .T extend between the bars 0 and nearly to the face of the cross J. These two sets of arms revolving in opposite directions thoroughly distribute the dirt or material which arises to them from the feed channels F, and the whole of the material is thus exposed to the action of the metal in the bath. It will be seen by the construction of this pan, with the interior pan, B, nearly filling it, that the amount of molten metal which is necessary within the pan is comparatively small. The upper part of the chamber H is contracted, so that the surface of the metal which is exposed at the top is very small indeed, and but little oxidation can take place.

In order to discharge the refuse material as it rises to the top of the molten metal, and to prevent a loss of the metal which would be carried off with the dirt if scrapers were used, I have fixed a pipe, P, across the top of the pan and just in the rear of the top of the charm ber II, this pipe being supplied with steam or compressed air from the boiler or any other suitable source. This pipe has a narrow slit or a series of small openings made along the side nearest to the chamber, and the blast of steam or air from it blows strongly across the surface of the metal, thus clearing away the dry refuse material as fast as it rises to the surface, and entirely separating it from any particles of the molten metal which may rise with it, and which will be too heavy to be blown oft by the blast. this apparatus I have found it useful to employ a current of electricity, which is passed through the bath by connecting the positive and negative wires with it in any suitable manner.

In connection with.

Having thus described my invention, what I claim as new, and desire to secure by Letters Patent, is-- 1. The pan A, having parallel sides and an inclined bottom, said pan having its lower side deepest, in combination with a second pan concentric with the pan A, provided at one side with the lead-chamber H and at the opposite side with a hopper, and a carrier between the bottoms of the two pans, and provided with peripheral raised flanges, forming channels into which the material from the feed-openiug falls, and means for rotating the carrier, substantially as herein described.

2. The outer pan, deeper at one side than at the other, an inner pan concentric therewith, provided at one side with the projectinglead chamber H and at the other side with a feedopening, a carrier between. the bottoms of the pans, having circular channels in line with the feed-opening, and means for rotating the carrier, in combination with inclined scrapers in the lead'chamber, having spades which it into the channels in the carrier and lift the material therefrom, substantially as herein described.

3. The outer pan with its inclined bottom, the inclined inner pan concentric therewith and provided at its deepest side with a projecting ,leadchamber and at its opposite or shallow side with a feed-opening, a channeled carrier rotating between the bottoms of the two pans, and inclined scrapers having spades fitting the channels and removing the material therefrom, in combination with a distributer in a chamber formed in the inner pan, said distributer consisting of concentric shafts having cross arms secured thereto, bars projecting from said arms in opposite directions, and means for rotating the arms and shafts in opposite directions, substantially as herein described.

4. An improved lead-bath apparatus comprising two eoncentric pans with inclined bottoms, one ,of said pans having a projecting lead-chamber at one side and feed-opening at the opposite side, a rotating carrier or disk between the bottoms of said pans and provided with channels in line with the feedopening, scrapers in the lead-chamber having spades fitting the channels in the carrier and removing the material therefrom, oppositelyrotatiug bars in the lead-chamber for distributing the material, and a blast-pipe over the top of the lead-chamber for discharging the refuse material arising to the top of the molten lead, substantially as herein described.

In witness whereof I have this day set my hand.

ANDREW M. SHIELDS.

\Vituesses:

S. H. NOURSE, H. 0. LEE. 

